This application claims the benefit of U.S. Provisional Patent Application No. 60/247, 849, entitled FAULT DETECTION AND ISOLATION SYSTEM AND METHOD and filed Nov. 9, 2000.
The present invention is in the field of vehicle control system design. More particularly, the present invention is a model-based fault detection and fault diagnosis system and method for monitoring overall vehicle system performance.
In recent years, increasing interest and requirement for improved vehicle performance, reliability, and safety has focused attention on the use of Fault Detection and Isolation (FDI) when designing vehicle control systems. Fault detection and isolation is becoming one of the most important aspects in vehicle system control design. In order to meet the increasing demand for better performance and reliability, model-based FDI schemes are being developed to address complete vehicle systems, to detect faults in sensors and actuators, and to apply appropriate corrective action without adding new hardware to the vehicle. However, the high complexity of most vehicle systems makes the standard FDI model-based technique difficult to apply without unacceptable computational effort.
The present invention is a novel system and method based on a hierarchical structure of the FDI scheme that reduces the computational effort of prior art systems. The FDI scheme uses the available sensors in a vehicle system and divides them into subsystems of smaller dimensions containing one or more modules that are related or interconnected. The same module may appear in a different subsystem, but the set of all subsystems does not have to contain all of the modules. For this structure, an FDI scheme comprising several detector units is created. Each detector unit receives information from the sensors and outputs a residual that is sent to a high-level detector unit which processes the data and performs the residual evaluation for the selected subsystem. Finally, each subsystem outputs a decision that is sent to a supervisor hazard detector performing the final diagnosis.